body{
    background-color: black;
}

h1,p{
    margin: 0;
    padding: 0;
}


/*页面宽度定义、居中*/
.wrapper{
    width: 1006px;
    background-color: cyan;
    margin: 0 auto;/*针对父容器居中*/
}

.clear{
    clear: both;
}

.header{
    width: 991px;
    background-color: greenyellow;
    margin: 0 auto;
    min-height: 200px;
}

.main{
    width: 991px;
    background-color: yellow;
    margin: 0 auto;
}

.footer{
    width: 991px;
    background-color: maroon;
    margin: 0 auto;
    min-height: 80px;
}

.main .sidebar{
    float: left;
    width: 742px;
    margin-right: 5px;
    background-color: blue;
    min-height: 600px;
}

.main .content {
    float: left;
    width: 244px;
    background-color: darkcyan;
    min-height: 600px;
}